FunctionWithCheckedException

import java.util.Date;
import java.util.Optional;

public class FunctionWithCheckedException {

    @FunctionalInterface
    public interface SomeAppropriateSemantic<T, R> {
        public R semantic(T t) throws CustomException;
    };

    public void method() {
        SomeAppropriateSemantic<String, Date> function = string ->
            new Date(Optional.ofNullable(string).orElseThrow(CustomException::new));
    }
}